Rotary jar



W. C. ERWIN April 11, 1939.

ROTARY JAR QSheets-Sheet 1 Filed Jan. 14, 1935 Mm w mw m

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April ,1, 9- w. c. ERWIN 2,153,882

ROTARY JAR Filed Jan. 14, 1955 3' Sheets-Sheet 2 r 1 am mw m m d a w Wm-lg v l hl April 11, 1939. Q wm 2,153,882

ROTARY JAR Filed Jan. 14, 1935 3 Sheets-Sheet 3 15g, 7

9a -W- Q 86 Inventor waldo Cir-win.

Patented Apr. 11, 1939 UNlTED STATES ROTARY J AR Weldon 0. Erwin, Huntington Park, Calif., assignor to John Grant, Los Angeles, Calif.

Application January 14, 1935, Serial No. 1,721

3 Claims.

This invention deals with oil well jars, and has for its general purpose to provide improvements in methods of jarring and jar structures that will greatly increase the effectiveness of this type of tool in removing objects that have become lodged in wells.

I-Ieretofore, the practice in operating rotary jars has been to attach to the lodged object a fishing tool carried on the drill pipe below the jar, to then place the drill pipe under longitudinal tension, and suddenly release (in'many instances as a result of the tensional pull) relatively movable parts of the jar which impact and produce a blow that is transmitted to the object. In such jars the stretch of the pipe is utilized as the means of producing the blow, since, when. a long drill pipe placed under great longitudinal strain is suddenly released at its lower end, the pipe in contracting develops a tremendous dynamic inertia and force.

After the jar parts have become released, they move relatively and freely a substantial distance in order that a blow of the desired magnitude may be generated, and during this time the connection, via the jar, between the drill pipe and unlodged object, is necessarily slackened. It is evident therefore that the drill pipe is effective as a means of exerting a pull on the lodged object, only prior to, and possibly after the jar release, and that during the interval between the points of release and impact, the pull on the object will be temporarily and completely interrupted. Likewise, in the usual type of jar, the relatively movable impacting parts can only be reset for a subsequent jarring operation by lowering the drill pipe, so that by no possibility can a continued pull be exerted on the object between successive blows. To my knowledge, no one in the past has been able to obtain the benefit of uninterrupted pull and concurrent jarring impact or a series of such impacts.

Now it is believed that the last named condition, 1. e. uninterrupted pull and concurrent impact, is the ideal one for most effectively dislodging an object, because by virtue of a sustained pull on the object, the latter is prevented from settling back to the position from which it is moved by the jarring blow, and thus the full benefit of each blow will be retained, until the object is finally loosened. Furthermore, by maintaining a sustained pull on the object, the latter can be loosened by much lighter blows than where impact alone is relied upon. Accordingly, this invention has been made with these objects 55 in View. Briefly, the present type jar is one in which delivery of the jarring impact and resetting are independent of longitudinal movement of the drill or strain pipe, so that a sustained pull may be exerted on the object at the same time one or a series of blows are delivered, 5 and throughout the intervals between successive blows.

Another object of the invention is to provide a jar in which the striking element is operated by fluid pressure, and particularly the hydro- 10 static pressure of the column of liquid standing in the well. Pursuant to this object, I provide Within the tubular body of the jar a plunger adapted to be driven upwardly into impacting engagement with a body or other surface, by well 1 liquid presure applied to its lower end. In the preferred form of the invention, the plunger is returned to its lower position simply by rotating the drill pipe and without the necessity for releasing the tension on the pipe.

All the above mentioned features of the invention, as well as-additional objects and details, will be more fully understood from the description to follow. Throughout the description reference is made to the accompanying drawings, in which:

Fig. 1 is a sectional view showing a preferred form of the invention, the striking plunger being in its uppermost position;

Fig. 2 is a similar view showing the plunger in its lowermost position;

Fig. 3 is a fragmentary perspective taken to illustrate more clearly the cam shoulders on the body and plunger;

Fig. 4 is a general view showing a drill pipe connected to a lodged object in the well, with a jar interposed above the fishing tool;

Fig. 5 shows a variational form of the general type of jar illustrated in Figs. 1 and 2;

Fig. 6 is a section looking down on line 6-6 of Fig. 5;

Figs. '7 and 8 are longitudinal sectional views showing two additional variant forms of the invention; and

Fig. 9 is a fragmentary perspective illustrating the locking device used in the jars of Figs. 7 and 8, for releasably connecting the plunger with the mandrel,

In Figs. 1 and 2, the body ID of the jar may be regarded as comprising barrel ll sorewthreaded at 12 to one end of a double pin coupling IS, the opposite end of which is threaded at M into the box end of pipe I5. The latter will in general practice be the rotary drill pipe, although it is to be understood that the jar may be operated by way of any suitable pipe or other means lowered in the well, and capable of being placed under longitudinal tension or strain during the course of operation of the jar. Therefore, I shall hereinafter refer to the pipe I5 broadly as the strain pipe. The body also includes a nut I6 threaded into the lower end of the barrel I I and providing a spline way for the mandrel as will presently appear.

The body contains a relatively longitudinally and telescopically movable mandrel II, the lower end of which is screwthreaded at I8 into a coupling I9 which connects the mandrel with a bit or fishing tool 23, or a pipe length which connects with such tool. It will be understood of course that the jar may be carried in the pipe string during drilling operations in order that if the bit becomes stuck the jar may be used to dislodge it, or that where the lodged object has become severed from connection with the pipe, the latter may be pulled and then again lowered with a fishing tool attached below the jar.

The mandrel carries a plurality of splines 26 which are received within ways 22 in nut I6 when the body is lowered from the position of Fig. 1. In this figure the parts are shown in their jarring positions, with the body elevated to bring the upper end of nut I6 into engagement with mandrel shoulder 23 formed by the mandrel enlargement or head 24. It will be noted that with the body thus elevated, mandrel splines 2I. terminate at 2Ia below spline ways 22 in nut I6, so that the body is free to rotate about the mandrel. During drilling operations, however, pipe I5 and the body ID are lowered to bring nut I6 into splined engagement with the mandrel, thereby transmitting rotation of l5 through the iar to the pipe or tool below.

A fluid pressure operated plunger 25 is contained within the body between coupling I3 and the mandrel enlargement 24. Fluid leakage from space 25 below the plunger into chamber 21 above the plunger, is prevented by a series of cup leathers 28 held between flanged rings 29, the cup leathers being tightly clamped between the rings by taking up nut 30 screwthreaded on the lower end of the plunger. Any fluid leaking into chamber 21 in an amount in excess of that required to fill the clearance space between the plunger and coupling I3 when the former is in its uppermost position, is discharged by the upward movement of the plunger through passage 3| and past check valve 32 into the well. Relative rotation between the plunger and mandrel I! is prevented by a mandrel extension I'la of substantially square cross section, projecting within a correspondingly shaped central way 33 in the plunger.

At this point it may be observed that the plunger is driven in its upward travel by the pressure of the column of liquid standing in the well, communicated to the lower end of the plunger by way of openings 34 in barrel II, and space 26. By reason of the extremely high hydrostatic pressure of the well liquid column, the plunger, when released from the position of Fig. 2, is projected upwardly at high velocity, causing its upper end 35 to strike surface 36 of the double pin coupling with such impact as to produce a heavy, upwardly directed jarring blow that is transmitted through the body and mandrel to the lodged object to which the fishing tool 28 is attached.

The plunger is returned to its lowermost position for delivery of a successive jarring blow by virtue of relative rotation of the body and through the action of a pair of cams, generally indicated at 31 and 38, formed on coupling I3 and the plunger, respectively. As shown most clearly in Fig. 3, the cam 31 on the coupling consists of a pair of substantially 180 spiral surfaces 39 separated by straight vertical shoulders 40, the cam 38 on the plunger comprising similarly shaped spiral surfaces 4I separated by vertical shoulders 42. As will be readily apparent, by rotating the strain pipe I5 in the direction of the arrow in Fig. 1 (and Fig. 3), the plunger 25 is cammed downwardly from its uppermost position by the engagement of the cam surfaces 39 and 4I, until the parts are rotated to the relative positions of Fig. 2. Upon continued rotation of the strain pipe, shoulders 40 and 42 move past each other, releasing the plunger for upward travel under the influence oi the fluid pressure applied to its lower end.

In order to explain most clearly the operation of the jar, reference is had to the general view of Fig. 4, in conjunction with Figs. 1 to 3. In Fig. 4, the strain pipe I5 is shown to be connected to a section of tubing 45, which may be taken as typical of an object lodged in the well, via the jar and fishing tool 20, shown typically as a spear tap threaded into the upper end of tubing 45. At the beginning of the jarring operation, pipe I5 is placed under tension and preferably is subjected to substantial longitudinal strain by exerting an upward pull through the conventionally illustrated draw-works 46 at the ground surface. After a stretch has been taken in the strain pipe, the latter is rotated to bring earns 37 and 38 into operation. As a result of continued rotation of the strain pipe, the plunger, after delivering a blow, is cammed down against the resistance of the well liquid pressure acting against its lower end, and is thus reset to deliver a subsequent blow. The frequency of the blows is of course controllable by varying the speed of rotation of the strain pipe.

It is important to observe that during and at the time the jarring impact is delivered by the plunger, the strain pipe is maintained under sustained upward pull and stretch, and hence that the upward pull on the object lodged in the well is uninterrupted at any time during the course of delivery of the jarring impact. Likewise, the same conditions obtain throughout the delivery of any number of successive impacts, since an uninterrupted pull is exerted on the object and a sustained stretch is maintained in the strain pipe throughout its continued rotation.

As illustrated in Fig. 4, the well liquid will usually stand at level L a considerable distance above the jar, so that the hydrostatic pressure applied to the lower end of plunger will be extremely high and the resultant impact produced by the plunger correspondingly great due to its speed of travel and the dynamic inertia of the liquid column. I may mention that if desired, the hydrostatic pressure of the well liquid column may be supplemented by additional fluid pressure communicated to the well casing 48 above the liquid level L, as by means of a pump 49 discharging gas or other fluid through line 50 into the top of the casing.

In Fig. 5, I show a form of the invention generally similar in principle to that of Figs. 1 and 2, but differing primarily in that the plunger is cammed down after each jarring impact by engagement with cam surfaces on the mandrel, instead of cams on the body, as in the first instance. The body 5| is shown to be connected by a double pin coupling 52 with a pipe or tool 53, the coupling having an upward extension 54 projecting within a central way 55 in the plunger 56, and preventing rotation of the latter within the body. As in the first described form, the well liquid pressure is communicated to the underside of the plunger through body ports 51. A nut 58 screwthreaded into the upper end of the body barrel has a counterbore 59 within the wall of which spline ways 69 are formed.

A telescopic mandrel, generally indicated at 5!, extends through nut 58 into the body, fiuid leakage between the central shank portion Gla of the mandrel and nut 58 being prevented by a suitable packing gland as indicated at 52. The upper enlarged portion Slb of the mandrel is screwthreaded into box end 63 of the strain pipe. In Fig. 5, the parts are shown in their jarring positions. During drilling, the mandrel is lowered relative to the body so as to bring the mandrel splines 54 within ways 60 and thereby enable the rotation of the strain pipe to be transmitted through the jar body to the pipe or tool 53.

The lower enlarged end Blc of the mandrel is shaped to provide cam surfaces 65 separated by vertical shoulders 66 (one only being shown in the sectional view) which engage similarly shaped cams 6'! formed on the plunger and separated by vertical shoulders 68. The shape of the cams will be recognized as corresponding to those previcusly described with reference to Fig. 3. Well liquid leaking past the plunger or mandrel into space 59 is expelled therefrom via central passage in the plunger, check valve H permitting fluid escape from space 69 and preventing its entry. A spring 72 confined between the lower end of the plunger and coupling 52, is provided to preclude the possibility of accumulation of sufiicient well liquid in space 69 to prevent the plunger from striking the mandrel in delivering the jarring blow. Spring 12 has sufficient expansion to project the plunger to its uppermost position, when released by cams 65, and to thereby displace well liquid that may have leaked into space 69 and which might otherwise remain due to a fluid pressure balance above and below the plunger when the plunger displacement and the volume of liquid in space 69 become equal.

In starting jarring operation, the mandrel is raised to bring shoulder 13 into engagement with nut 58 and a stretch is taken on the strain pipe 53. Then by continued rotation of the strain pipe, the jarring plunger 56 is successively moved down by cams 65 and 61 and released for upward travel under the influence of the well liquid pressure applied to its lower end. In this case, the plunger delivers its jarring blow against the mandrel, the upper end of the plunger striking mandrel surface Gld.

The type of jar shown in Figs. 7 and 8 also operates to deliver an upwardly directed blow while a sustained pull is exerted on the lodged object via the strain pipe. However, in this instance, the operation of the jar differs from the operation of the previously described forms primarily in that lowering of the strain pipe is required to reset the jar for successive jarring operations. In Fig. 7, the mandrel l5 connected at ts lower end to the pipe or tool 16, telescopes into the lower end of the body barrel Tl, the mandrel and body being relatively rotatable in their jarring positions, as illustrated. To impart rotary drive from the body to the mandrel during drilling, the body is lowered so that the mandrel splines 18 are received within ways 19 in nut 80. The upper end of the body is connected by coupling 8| with the strain pipe 82, the coupling having a laterally opening bore 85 for conducting the circulating fluid. It may be mentioned that if desired, coupling l3 in the first described form may be similarly drilled to provide a circulating fluid passage.

A vertically movable plunger 86 is contained within the body, the previously described type of packing 85 being provided to prevent leakage of Well liquid into chamber 86. Using this type of packing, i. e. expansible cup leathers, the latter will be forced out by the well liquid pressure into such tight engagement with the body as to cause the plunger to rotate with the body in the hereinafter described operation of locking the plunger to the mandrel. The lower end of the plunger has an extension 81, which, in the position of Fig. '7, is received within bore 88 in the upper end of the mandrel. It may be stated at this point and with reference to the general mode of operatic-n, that the plunger is releasably locked to the mandrel until the desired pull or tension has been taken in the strain pipe, and that at that point, the. plunger is released from the mandrel to be driven upwardly into striking engage- 7 ment with coupling 8| by well liquid pressure communicated to the plunger through ports 89.

Broadly speaking, any suitable means may be provided as a releasable connection between the plunger and mandrel. As typical, however, I have shown the plunger extension 8? to carry a pair of cam shaped lugs 90 adapted to be received within slots 9i, see Fig. 9, formed in the top tubular portion of the mandrel. This slotted lug receiving part of the mandrel is shaped to provide downwardly sloping cam surfaces 92 in. order that after the plunger has been released from the mandrel to strike the jarring blow, and is then moved down to reengagement of the mandrel, as will presently appear, the bottom cam surfaces 90a. of the lugs 90 will engage the mandrel cams 92, causing the-plunger to bodily rotate and the lugs to turn into slots 9|.

In the operation of the jar, the body is raised to bring nut 85 into engagement with mandrel shoulder 95 and a longitudinal tension is taken on the strain pipe. Then the strain pipe and body are rotated in the direction of the arrow, such rotation being accomplished by rotation of the plunger 84 so as to withdraw lugs 99 from slots 9| and free the plunger for upward travel. Shoulders i l0 and I I l on the mandrel and plunger lugs, respectively, will be sufliciently inclined so that while preferably less than the slip angle, the frictional engagement between the plunger and body will disengage them. upon rotation of the body. It will be noted that during the plunger releasing operation and subsequent jarring travel of the plunger, a sustained pull will continue to be exerted on the lodged object via the body and mandrel. In order to reset the jar, the strain pipe is lowered with plunger 84 remaining substantially in engagement with coupling 8| following the jarring impact until lugs 90, through engagement with cams 92, are rotated into slots 9|. The body is then raised to the jarring position shown, and the described operations repeated until the lodged object has been removed.

In the described operation of resetting the jar, it will be noted that as a result of downward movement of the body relative to the mandrel (and plunger after the latter has reached its lowermost position), any well liquid that may have leaked into chamber 86, will be forced out through passage 96 and past check valve 91.

The further variational form shown in Fig. 8 is similar to that of Fig. '7 as to operation and structure, with the exception that provision is made for maintaining a passage of circulating fluid through the jar, instead of diverting it via passage in the upper coupling. In Fig. 8 a circulating fluid pipe 98 connected to coupling 99 at I extends continuously through the plunger IM and the mandrel I02 into the connection I03 between the mandrel and tool I04. Fluid leakage between pipe 98 and the plunger is prevented by a suitable packing gland I06 carried by the latter. Preferably the lower end of the circulating fluid pipe will also be packed off, as by means of a gland I85 within the coupling I03. As will be apparent, the provision of an open circulating pipe extending entirely through the jar enables a continuous flow of circulating fluid to be maintained during all periods of operation.

I claim:

1. In a jar connecting a pipe with an object lodged in a well, a tubular housing, a member connected thereto and adapted to make connection with the object, a vertically movable striking element in the form of a plunger in the housing, means connecting the striking element with said connecting member to allow vertical movement but restrain rotary movement of the element, means connectingthe housing with the pipe, the pipe and striking element being relatively rotatable, and cam means connected with the pipe and the striking element whereby the element is moved longitudinally in one direction by rotation of the pipe, and means admitting fluid pressure from the Well to the housing at one side of the plunger striker to move it in the opposite direction.

2. In a jar, a vertical tubular housing, a longitudinally movable plunger in the housing, a pipe connection member rigidly attached to the upper end of the housing, a mandrel limitedly slidable in the lower end of the housing and adapted to be connected to an object in a well, means rotatively connecting the housing and mandrel when the housing is moved down on the mandrel and freeing the housing and mandrel for relative rotation when the housing is moved up, means rotatively connecting the mandrel and plunger but allowing relative longitudinal movement therebetween, the housing having an opening admitting fluid pressure from the well to the housing inte rior under the plunger, and cam means connectcd with the housing and the plunger to cause downward movement of the plunger on rotation of the pipe and the housing.

3. In a jar, a vertical tubular housing, a longitudinally movable plunger in the housing, a pipe connection member rigidly attached to the upper end of the housing, a mandrel limitedly slidable in the lower end of the housing and adapted to be connected to an object in a well, means rotatively connecting the housing and mandrel when the housing is moved down on the mandrel and freeing the housing and mandrel for relative rotation when the housing is moved up, the housing having an opening admitting fluid pressure from the well to the housing interior under the plunger, and cam means connected with the mandrel and the plunger to cause downward movement of the plunger on rotation of the pipe, housing and plunger relative to the mandrel.

WELDON C. ERWIN. 

